1. Field of the Invention
The present invention relates to display devices, and particularly to a display device for outside installation.
2. Description of Related Art
Conventionally, as a monitor for image display, often used are flat-panel displays such as a liquid crystal display. Most of the conventional liquid crystal displays are designed assuming that they are installed indoors, and the measures to protect the liquid crystal display against weather, dust or the like are not taken. Thus, it has been difficult to permanently install the conventional liquid crystal display outdoors.
However, in recent years it is desired that a liquid crystal display is permanently installed outdoors. The reason includes the fact that the liquid crystal display has a small thickness and that the resolution of the image is high. The small thickness allows the installation of the display on the outer wall of the building or in narrow places such as a bus stop. In addition, the high resolution allows an image to be displayed clearly even if the display screen is small.
Therefore, thought is an attempt to arrange a liquid crystal display, particularly an image display panel which is easy to be damaged by weather and dust among liquid crystal displays, in the inside of an accommodation room that has a waterproof structure in order to protect the liquid crystal display from weather and dust.
However, since there is no escape of heat from the inside of the accommodation room to the outside when the image display panel is arranged in the inside of the accommodation room and it is waterproofed, the image display panel cannot be air-cooled naturally. Thus, a blackout occurs. The blackout is a phenomenon in which the temperature of the image display panel rises due to the heat generated from an image display panel in operation or the sun light, and an original function of the liquid crystal falls to disable the image display.